London, 1883: All is quiet at 125 Gower Street. So, when a young woman turns up at the door, imploring London's foremost personal detective, Sidney Grice, to solve her father's murder, Grice can barely disguise his glee. Mr Nathan Garstang was found slaughtered, with no trace of a weapon or intruder. A classic locked-room case. But what piques Grice's interest is the link to the unsolved murders of Nathan's uncle, aunt and servants in the very same house...